Anne and maria play tennis almost every weekend.  So far, Anne has won 12 out of 20 matches.

 

a.  How many matches will Anne have to win in a row to improve her winning percentage to 75%?

b.  How many matches will Anne have to win in a row to improve her winning percentage to 90%?

c.  Can Anne reach a winning percentage of 100%?

Maria spends $12 on lottery tickets every week and spends $126 per month on food.
on an annual basis,the money spent on lottery tickets is how much of the percentage of the money spent to buy food

So I am trying to figure this percentage out and I feel stupid. For a 150$ meal, say the tip was 70$, with a total of 220. Why when you are trying to figure out the tip percentage do you do 70/150. Isn't the part/whole 70/220?